Elasticsearch - tf-idf computation for each alias in shard

Question

Considering I have three customer accounts and the data of three accounts are stored in three aliases in the single index which is distributed across three shards.

For a given query, how is the tf-idf calculated? Since it is in the single index does the term count is considered with all three account's data/aliases. I would like to know if we can restrict the term frequency count and IDF only to the account/one alias

Answer 1

If you are using routing with your aliases it will use specific routing to find the shards and will calculate the tf-idf on that specific shards otherwise your tf-idf is calculated based on index. For more information you can check custom routing in ElasticSearch here and here .

Update:

Index and shard definitions:

Data in Elasticsearch is organized into indices. Each index is made up of one or more shards. Each shard is an instance of a Lucene index, which you can think of as a self-contained search engine that indexes and handles queries for a subset of the data in an Elasticsearch cluster.